Televisions (or monitors) typically display images in the form of image frames, which are continuously refreshed, for example, with a 50 Hz or 60 Hz frame rate. Some of the televisions such as ones using spatial light modulator (SLM) light processing technology, typically use the entire frame time (tf, the time separating the receipt of new images) to display each image.
When there is motion in images, a viewer will unconsciously “track” the motion across the screen with his/her eyes. This eye-tracking causes the viewer's retina to move while the television is trying, in essence, to “paint” the image on the viewer's retina. This causes the viewer to perceive motion artifacts in the images. Depending on the amount of motion, a variety of motion artifacts such as image softening/blurring, boundary dispersion artifacts, pulse width modulation (PWM) artifacts, color separation, and the like, can be generated.
These motion artifacts can be significantly reduced by increasing the frame rate of the images. This reduces the amount of time that an individual image is displayed on a viewer's retina, thus reducing the opportunity for eye-tracking to generate the artifacts. It is hence preferable to have a high frame rate on televisions, especially those using SLM technologies.
Various methods have been explored to increase the frame rate. However, the existing techniques cause a significant increase in processing bandwidth and system complexity. For example, TV manufacturers have used a number (two or more) of individual frames of “real” data to calculate a new image, and to interpolate (or extrapolate) the new image between two existing images. As a result, the frame rate is essentially at least doubled. For example, frames of 60 Hz frame rate have a frame time of 16.67 milliseconds. By interpolating a new image between each pair of real images, the frame rate may be doubled to 120 Hz. Accordingly, the display time for each image is reduced to about 8.33 milliseconds. The motion artifacts are thus reduced.
The above-discussed solution suffers drawbacks, however, when the frame rate is doubled, for example, from 60 Hz to 120 Hz. This not only requires the calculation bandwidth to be doubled, but also requires all of the downstream video processing, such as any subsequent signal processing and the final display processing of the TV itself, to support the increased bandwidth. The circuitry for processing the images will also have to process twice the bandwidth or more. Therefore, the costs for designing and manufacturing the respective circuitry is increased.